460 NATURAL HISTORY OF BIRDS. 



mesomyodian type, A representing the former, B the latter. The acromyodian form 

 here figured is not quite typical oscinine, but the attachment of the intrinsic muscles 

 to the ends of the semi-rings is well represented, while the median insertion is equally 

 plain in the other figure. 



The classification of the Passeres has recently made a long stride forward, espe- 

 cially by the investigations of Professor Garrod. We have above indicated three pri- 

 mary divisions of the order, which we shall designate as super-families, to which we 

 may add two additional ones, the Eurylaimoidea?, and the Menuroideas ; the three 

 others are the Tyrannoideaa, corresponding to the non-tracheophonous mesomyodian s, 

 the Formicaroideas, being the equivalent of the TracheophonaB of authors, and the 

 Passeroidea?, of the same limits as the Oscines proper, or the Acromyodi of Garrod, 

 minus the Pseudoscines of Sclater. These five super-families to be arranged as follows : 



Tensor patagii brevis picarian ............ Menuroidew. 



syrinxbroncho-tracheai { j^ '** 



-Tensor patagii ( mesomyodian ^^ Formicaroide( schizopelmous. 



brevis passerine J acromyodian . . v ......... Passeroidece 



On the whole the MENUROIDE^E may be regarded as the most abnormal Passeres, 

 and in many respects most generalized. It is true that their syrinx is ' acromyodian,' 

 inasmuch as the intrinsic muscles are fastened to the ends of the semi-rings, but there 

 seems to be nothing to necessitate the theory of the true oscinine syrinx having been 

 developed from this ' pseudoscinine ' one, or to prevent the assumption that both 

 these styles have developed independently from the mesomyodian pattern, as they are 

 sufficiently diverging in other points than the number of the intrinsic muscles to 

 make it probable that they are of independent origin. It is also true that they are 

 schizopelmous, and that the Eurylaimoidea3, which we have placed after them, are 

 more generalized in this respect, being, as they are, desmopelmous ; but there is noth- 

 ing strange in supposing that the vinculum has been lost independently in the birds of 

 the present group and in those of the three last super-families of our scheme ; in 

 other words, that the vinculum was lost by the ancestors of this super-family and in 

 those mentioned after the ancestral passerine stock had split into two groups, charac- 

 terized by the difference in the arrangement of the tensor patagii brevis, besides in 

 several osteological features. The proof of the admissibility of this conclusion is 

 furnished by the fact that not only has a Picarian group viz., the hoopoes de- 

 veloped the same arrangement of the deep plantar tendons, but that even several 

 herons have lost the vinculum connecting the flexor hattucis with the flexor per- 

 forans. 



The osteological features by which the members of the present super-family deviate 

 from the other Passeres are many, but we shall only mention those by which the two 

 families which constitute the super-family may be at the same time separated. The 

 lyre-birds have quite a peculiar breast-bone, it being long, and much constricted near 

 the centre ; the manubrium is very well developed and furcated ; the posterior edge 

 is strongly convex, and has only a slight notch on each side near the margin, quite 

 different from all other Passeres. The clavicles are well developed, but without a 

 median process at the symphysis. On the other hand, the sternum of the brush-birds, 

 as figured by Garrod, differs very much from the above. The manubrium is less de- 

 veloped, though furcate, and the posterior edge is straight, with a deep passerine notch 



